<form action="usercp.php?action=myteams" method="post" onSubmit="return confirm('<?= $lang['Confirm'] ?>');">

  <tr>
  	<input name="teamid" type="hidden" value="<?= $teamid ?>">
    <td class="tableButtonLeft"><?= $teamname ?></td>
    <td class="tableButtonLeft"><?= $memberinfo ?></td>
    <td class="tableButtonLeft"><input class="controlinput2" name="leaveTeam" type="submit" value="<?= $lang['LeaveButton'] ?>"></td>
  </tr>
</form>